Google Map of P-3 AEW Sentinel at Corpus Christi NAS

The Lockheed Martin P-3 AEW Orion was developed using ex-Royal Australian Air Force and US Navy P-3B airframes, combined with the APS-125 Radar and Mission System (later retrofitted with an APS-138 system) from the United States Navy E-2 Hawkeye carrier-borne AEW&C aircraft. The United States Customs Service, which is at this time the sole user of the P-3 AEW, took delivery of the first one in 1988 and since 1993 has been operating a fleet of four aircraft for counter-narcotics missions in the US particularly over the Gulf of Mexico and the Caribbean. Other radars fitted to the P-3 AEW to fulfill the counter-narcotics mission includes the Hughes APG-63U, derived from the radar used in early model F-15 Eagle fighters.